Advances in hardware display technology have provided great diversity in display devices. For example, contemporary display screens vary from approximately two inches (such as for cell phones), to fifteen to twenty inches (such as for laptops and desktops), to several feet (such as with for media centers). There are also other differences in display types as well, e.g., aspect ratios may differ. Further, different users need diverse display characteristics, as users have different levels of visual acuity, for example, which requires different display characteristics such as font size.
These differences in device and end-user characteristics present a challenge for content developers, who need to create content that can dynamically adapt to changes in device or zoom factor. For example, a user may move the same piece of content from using a tablet PC on a crowded commuter train to a high-resolution media center at home. Very little if any content can dynamically adapt to be comfortably consumed by users across such a wide range of scenarios.